How do I avoid creating duplicate records while importing?

While importing records, you can identify the duplicate records based on a unique field for each type of record. These are the fields for each type of record based on which you can check for duplicates:

Leads - Email
Contacts - Email
Accounts - Account Name
Deals - Deal Name
Cases - Subject
Solutions - Title
Campaigns - Campaign Name
Vendors - Vendor Name
Products - Product Name

Scenario:

You do not use any of the fields mentioned above and want to update a list of records with additional details. While importing a file with those updated records, you want to check for duplicates.

In such cases, you can use the Record ID to check for duplicate records. Each record in Zoho CRM has a unique ID. When you export these records, you get their individual Record IDs. Follow these steps to check for duplicate records while importing:

Export the records that you wish to update. The exported file will include the Record IDs.
Make the necessary changes to the records in the file.
Import the file in Zoho CRM using the Overwrite option.

Duplicates will be checked based on the record IDs.
When a duplicate record is found in Zoho CRM, it will be overwritten with the data in the import file.
Only the mapped fields will be overwritten.
If the Record ID field is not mapped, new records will not be created.